Thanks a lote for your useful comments.
GM.
El jue., 7 jul. 2022 11:09, Niranjana K M escribió:
> Apart from just looking at this particular plot and trying to manage it,
> look at the actual problem in depth. Please look at how plotting points are
> evaluated. Even though Sage is capable of ev
Apart from just looking at this particular plot and trying to manage it,
look at the actual problem in depth. Please look at how plotting points are
evaluated. Even though Sage is capable of evaluating these points, it (or
matplotlib?) is evaluating y coordinates after 88 as inf or nan.
Please see
In case the hope in extending the range of t further and further
was to capture the missing portion of the curve, it turns out
the problem is at the other end, near zero.
The curve is missing its initial segment, because
- parametric_plot(C, (t, a, b)) uses equispaced evaluation points
along th
I agree with Samuel that the numbers involved are huge.
After
sage: xtn,xtd=xt.numerator_denominator()
sage: ytn,ytd=yt.numerator_denominator()
one can see that
xtn ~ - e^(2*t)
xtd ~ e^(2*t)
ytn ~ e^(8*t)
ytd ~ 2*e^(8*t)
However, SageMath has no problems evaluating it:
sage: *for* i in s
Also the following:
> parametric_plot(C, (t,89.0,95.0))
.
verbose 0 (2200: graphics.py, get_minmax_data) ymin was NaN (setting to 0)
verbose 0 (2200: graphics.py, get_minmax_data) ymax was NaN (setting to 0)
> parametric_plot(C, (t,89,95))
.
verbose 0 (2200: graphics.py, get_minmax_data)
Some thing happened after t=89. Is it because of the following two cases:
for T in srange(1,100,1.0):
print(T, float(C(T)[0]), float(C(T)[1]))
.
87.0 -0. 0.5001
88.0 -0. 0.5
89.0 -1.0 0.5
Sorry, my message was incomplete.
So yes, there is a problem.
On Mon, 4 Jul 2022 at 16:14, G. M.-S. wrote:
>
> Hi Gema.
>
> Doing
>
> sage: xt,yt=C[*0*],C[*1*]
>
> sage: xt.taylor(t,oo,*3*)
>
> -6*t^4*e^(-3*t)*log(t)^2 - 3*t*e^(-2*t)*log(t)^2 - 1
>
> sage: yt.taylor(t,oo,*3*)
>
> 1/2*t*e^(-2*t)
Hi Gema.
Doing
sage: xt,yt=C[*0*],C[*1*]
sage: xt.taylor(t,oo,*3*)
-6*t^4*e^(-3*t)*log(t)^2 - 3*t*e^(-2*t)*log(t)^2 - 1
sage: yt.taylor(t,oo,*3*)
1/2*t*e^(-2*t)*log(t)^2 + 1/2*(2*t^4*log(t)^2 + t*log(t)^3)*e^(-3*t) + 1/2
sage:
you see that it converges towards (-1, 1/2) exponentially quickl
Hello,
I've the following curve,
t=var('t')
C=[(-exp(2*t) + (-t^2 - 2*t)*ln(t)^2 - t^6 + 2*exp(t)*t^3)/(exp(2*t) + (t^2
- t)*ln(t)^2 + t^6 - 2*exp(t)*t^3), ((28*t^18 + 60*ln(t)^2*t^14 +
36*ln(t)^4*t^10 - 10*ln(t)^3*t^10 + 4*t^6*ln(t)^6 - 6*ln(t)^5*t^6)*exp(2*t)
+ (-56*t^15 - 80*ln(t)^2*t^11 -
